It is common practice in water and/or waste water filter systems to employ a rotary agitator or sweep adjacent the upper surface of a particulate filter bed, to assist in the cleaning of the filter bed during a backwashing operation. These agitators include an elongated, rotary arm disposed in a horizontal plane and including a plurality of nozzles connected thereto along its axial length, for directing fluid from the rotary arm at a high velocity into engagement with particles of a filter bed.
It is quite common in the above described rotary sweeps to include nozzles at the axial ends of the rotary arm, to directed fluid into in engagement with filter bed particles in regions of the filter located radially outwardly from the rotary arm. In sweeps employing only one nozzle at each axial end of the rotary arm, a threaded rear end of the nozzle has been threaded into each respective end of the arm.
In sweeps including multiple end nozzles a short section of pipe has been provided with an opening through the peripheral wall thereof, and then welded perpendicular to the axial end of the rotary arm, with the opening through the peripheral wall of the short section of pipe aligned with the central passageway through the rotary arm. This short section of pipe formed a T-shaped plenum chamber, which has been tapped to accommodate a plurality of individual nozzles. This arrangement is undesirably complex, involving the assembly of a large number of components, including the individual components of each of the separate nozzles.
A prior art nozzle utilized in rotary sweeps is disclosed in U.S. Pat. No. 3,351,292 issued to Stuart, Sr. In this construction a cap member is provided with a single X-shaped incision aligned with a central passageway through a rear section of the nozzle, A forward wall of the rear nozzle section functions to engage lips provided by the X-shaped incision through the cap member to prevent the lips from moving inwardly when flow through the nozzle is interrupted, and thereby prevent foreign debris, such as debris collected by the filter bed, from entering and clogging the nozzle. An important feature of this invention is to locate the X-shaped incision in alignment with the central flow passageway through the rear section of the nozzle.